1. Field of the Invention
The present invention relates to a semiconductor device-equipped with fuses and a method of manufacturing the same.
2. Description of the Related Art
In a semiconductor device, a fuse is used to relieve a defect by redundancy substitution in a memory and control or adjust a resistance value employed in a resistance circuit, i.e., trim the resistance value. One example of a conventional fuse is shown in Japanese laid-open Patent No. 2000-243213.
The present fuse is vertically disposed on the surface of a substrate. The fuse penetrates an insulator layer and is connected to a conductive path on the surface of the substrate. The fuse has an advantage that the area occupied by the fuse on a semiconductor chip becomes small owing to the vertical provision of the fuse in this way.
The fuse is blown by Joule heat of a current that flows through the fuse itself. The Joule heat rises as the cross-sectional area thereof becomes small, and the fuse is apt to melt down. The more the fuse is reduced in size, the more the semiconductor device can be scaled down. This is because the size of a portion which is connected to the fuse and causes a fuse blowing current to flow therethrough can be reduced in accordance with the fuse as well as the ability to reduce the size of the fuse.
With the scaling up of an integrated circuit constituting a semiconductor device in particular, the number of fuses mounted on one chip tends to increase. The influence of the sizes of individual fuses on the overall size of the chip is becoming increasingly significant.
Therefore, the conventional fuse has a problem in that its cross-sectional area could be merely reduced to the minimum size defined by a micro-fabrication technique.